The contest to replace Caroline Lucas MP as the next leader of the Green Party has stepped up a notch after two party members announced their candidacy.

Wales Green Party spokeswoman Pippa Bartolotti confirmed last night that she would stand in the leadership election expected to take place in early September.

"It's high time there was some healthy competition for this role, and I'm hoping several people will put their name forward," she wrote on Facebook.

"The Greens need to open up the debate and forge a robust direction. Maybe I'm too straight talking for some, but I am prepared to stand up and tell it like it is."

Peter Cranie also kicked off his bid to lead the Green Party today with a campaign seeking to attract voters who are disillusioned by the Coalition's programme of spending cuts.

If elected as Green Party leader, he hopes to make the Greens more efficient, increase its membership with a more strategic approach to fundraising, and give greater support to local parties seeking to win council seats.

"There's a large sector of the electorate that's vehemently opposed to the austerity agenda," Cranie told BusinessGreen. "And the only party offering them the policies they want is the Green Party."

He has also long argued for major government investment in green technology. As a Euro-election candidate in 2009 he helped launch the Green Party's Euro-election manifesto, which proposed a package of government investments calculated to generate a million new jobs in the UK.

"It's widely known that renewable energy sustains more jobs per unit of power than fossil fuel or nuclear energy," Cranie said. "As Green Party leader I would work hard to get this message across to the public, that green energy policies are especially jobs-rich."

Cranie added that increased investment in green industries could help to create jobs in other parts of the supply chain, such as plumbers, builders and electricians.

"Instead of concentrating jobs at a few big power stations we'd be spreading those jobs throughout Britain's communities," he said.

According to Cranie's office, the election will be held by postal ballot of all Green Party members under a single transferable voting system in September 2012. The new leader will then serve a two-year term.

Lucas confirmed last month that she would not seek another term in order to help better challenge the Lib Dems at the next election. The party is hoping for further gains at the 2014 European elections and the 2015 general election.

Cranie, who describes himself as an anti-racism activist, is also planning to contest the North West European Parliament seat in 2014 against BNP leader Nick Griffin.

He is the first candidate to announce his intention to stand for the post of leader, while the only candidate for deputy leader is councillor Alex Phillips, who serves in the Party's only ruling council group in Brighton and Hove.

Jenny Jones, the Green Party London Assembly Member, who last month beat Lib Dem Brian Paddick into fourth position in the capital's mayoral election, has already ruled herself out of the leadership competition.